Skip to content
Inciteful Med

Understanding Your Lab Reports

Last updated:

Multiple myeloma lab reports track disease burden using the M-spike and free light chain ratio. The M-spike measures abnormal antibodies, while the Kappa/Lambda ratio tracks lighter protein fragments. Beta-2 Microglobulin (B2M) and albumin levels help determine the disease stage.

Key Takeaways

  • • The M-spike on the SPEP test measures the burden of abnormal cancer antibodies in the blood.
  • • The free light chain (Kappa/Lambda) ratio tracks disease activity with a normal range of 0.26 to 1.65.
  • • Beta-2 Microglobulin (B2M) and Albumin levels are combined to determine the International Staging System (ISS) stage.
  • • Patients with 'Light Chain Only' myeloma rely on light chain ratios and urine tests rather than the M-spike for monitoring.
  • • High calcium levels in lab reports may indicate active bone damage caused by the myeloma.

Reviewing your lab reports can feel like learning a new language. These tests measure the “burden” of the disease. By tracking these numbers, you can see exactly how well your treatment is working [1][2].

The M-Spike: Your Personal Barometer

The M-spike (monoclonal protein) is found on the SPEP (Serum Protein Electrophoresis) test [3].

  • What it is: A measurement of the abnormal antibodies produced by the cancer [4].
  • Goal: To see this number drop to zero (Complete Response) [1].

Free Light Chains: The “Ratio”

Some myeloma cells only produce smaller pieces called Free Light Chains (Kappa and Lambda) [5].

  • The Ratio: Doctors watch the Kappa/Lambda ratio. Normal is 0.26 – 1.65 [6].
  • Light Chain Only Myeloma: About 10% of patients don’t have an M-spike. For them, this test (and the 24-hour urine test) is the primary way to track the disease [5][7].

Immunofixation (IFE): The “Flavor”

While SPEP tells you how much, IFE tells you what kind [3].

  • Types: IgG, IgA (common) or IgM/IgD/IgE (rare).
  • Light Chain: Kappa or Lambda.
  • Why it matters: Knowing you are “IgG Kappa” ensures doctors track the right markers [8].

Staging Markers

  • Beta-2 Microglobulin (B2M): High levels (>5.5>5.5 mg/L) indicate more active disease [9][10].
  • Albumin: Low levels (<3.5<3.5 g/dL) can indicate advanced stage [9].
Marker Typical Normal Range Significance in Myeloma
M-Spike 0 g/dL Measures tumor “burden”
FLC Ratio 0.26 – 1.65 Tracks light chain activity
B2M < 3.5 mg/L Used for staging (Lower is better)
Albumin ≥\ge 3.5 g/dL Used for staging (Higher is better)
Creatinine 0.7 – 1.3 mg/dL Measures kidney function
Calcium 8.5 – 10.5 mg/dL High levels indicate bone damage

Note: Reference ranges vary by lab. [11]

Frequently Asked Questions

What is the M-spike in myeloma test results?
The M-spike represents the amount of abnormal monoclonal protein (antibody) produced by myeloma cells. It is measured via the Serum Protein Electrophoresis (SPEP) test, and the goal of treatment is typically to drive this number down to zero.
What is a normal free light chain ratio?
The normal range for the Kappa/Lambda free light chain ratio is typically 0.26 to 1.65. Doctors monitor this ratio to track disease activity, especially in patients who do not have a measurable M-spike.
What does a high Beta-2 Microglobulin (B2M) level mean?
Beta-2 Microglobulin (B2M) is a protein used to stage multiple myeloma. Higher levels (above 5.5 mg/L) generally indicate more active or advanced disease, while lower levels suggest a better prognosis.
How is 'Light Chain Only' myeloma tracked?
Approximately 10% of myeloma patients do not produce the complete antibodies measured by the M-spike. These patients have 'Light Chain Only' myeloma, and their disease is tracked primarily using the free light chain test and 24-hour urine tests.
Why do doctors check creatinine in myeloma patients?
Creatinine levels are measured to monitor kidney function, which can be affected by myeloma. A normal range is typically 0.7 to 1.3 mg/dL, though this can vary slightly by lab.

Questions for Your Doctor

  • • What is my current M-spike value, and what was it at diagnosis?
  • • Is my free light chain ratio moving toward the normal range (0.26–1.65)?
  • • Based on my B2M and Albumin, what is my ISS stage?
  • • If I have 'Light Chain Only' myeloma, are we tracking my 24-hour urine results as well?
  • • How is my kidney function (creatinine) holding up?

Questions for You

  • • Have I noticed any changes in the color or 'foaminess' of my urine?
  • • Am I reviewing my lab results before my appointments?
  • • Do I understand which specific number (M-spike vs Light Chains) is the best tracker for *my* disease?

Want personalized information?

Type your question below to get evidence-based answers tailored to your situation.

References

  1. 1

    Prognostic Impact of Serum Free Light Chain Ratio Normalization in Patients with Multiple Myeloma Treated within the GMMG-MM5 Trial.

    Klein EM, Tichy D, Salwender HJ, et al.

    Cancers 2021; (13(19)) doi:10.3390/cancers13194856.

    PMID: 34638344
  2. 2

    Involved free light chain: an early independent predictor of response and progression in multiple myeloma.

    Gran C, Afram G, Liwing J, et al.

    Leukemia & lymphoma 2021; (62(9)):2227-2234 doi:10.1080/10428194.2021.1907370.

    PMID: 33797301
  3. 3

    Should routine laboratories stop doing screening serum protein electrophoresis and replace it with screening immune-fixation electrophoresis? No quick fixes: Counterpoint.

    Smith JD, Raines G, Schneider HG

    Clinical chemistry and laboratory medicine 2016; (54(6)):967-71.

    PMID: 26677889
  4. 4

    Cutaneous Multiple Myeloma.

    Miriyala LKV, Avasthi D

    Cureus 2021; (13(9)):e17779 doi:10.7759/cureus.17779.

    PMID: 34659990
  5. 5

    Diagnosis and monitoring for light chain only and oligosecretory myeloma using serum free light chain tests.

    Heaney JLJ, Campbell JP, Griffin AE, et al.

    British journal of haematology 2017; (178(2)):220-230 doi:10.1111/bjh.14753.

    PMID: 28573706
  6. 6

    Diagnostic reference range of κ/λ free light chain ratio to screen for Bence Jones proteinuria is not significantly influenced by GFR.

    Schmidt-Hieltjes Y, Elshof C, Roovers L, Ruinemans-Koerts J

    European journal of haematology 2016; (96(5)):527-31 doi:10.1111/ejh.12632.

    PMID: 26172558
  7. 7

    Serum-free light chain test utilisation at a South African academic laboratory and comparison with serum protein electrophoresis results.

    Banderker RB, Fazel FB, Zemlin AE, et al.

    African journal of laboratory medicine 2023; (12(1)):2201 doi:10.4102/ajlm.v12i1.2201.

    PMID: 38058849
  8. 8

    Monoclonal Gammopathy Presenting with Pseudo Biclonal Pattern in Serum Protein Electrophoresis - An Interesting Perspective of Case Series.

    Nethaji K, Elango K, Selvarajan S, Krishnamurthy S

    EJIFCC 2025; (36(3)):387-393.

    PMID: 41098216
  9. 9

    Revised International Staging System for Multiple Myeloma: A Report From International Myeloma Working Group.

    Palumbo A, Avet-Loiseau H, Oliva S, et al.

    Journal of clinical oncology : official journal of the American Society of Clinical Oncology 2015; (33(26)):2863-9 doi:10.1200/JCO.2015.61.2267.

    PMID: 26240224
  10. 10

    Analysis of Ubiquitin-Conjugating Enzyme E2T (UBE2T) Protein Levels in the Bone Marrow Biopsy Specimens of Patients With Multiple Myeloma.

    Wang F, Yu N, Xia R

    Cureus 2025; (17(4)):e82571 doi:10.7759/cureus.82571.

    PMID: 40259951
  11. 11

    Evaluation of a new free light chain ELISA assay: bringing coherence with electrophoretic methods.

    Jacobs JFM, de Kat Angelino CM, Brouwers HMLM, et al.

    Clinical chemistry and laboratory medicine 2018; (56(2)):312-322 doi:10.1515/cclm-2017-0339.

    PMID: 28771430

This guide explains myeloma lab report terminology for educational purposes. Your hematologist or oncologist is the best source for interpreting your specific test results and prognosis.

Stay up to date

Get notified when new research about Multiple Myeloma is published.

No spam. Unsubscribe anytime.